Low-Noise Detection System using an InGaAs PIN Photodiode with a Charge Integrating Amplifier

Abstract

We developed a low noise detection system using an InGaAs-PIN photodiode for near infrared spectroscopic measurement. Since no practical photomultipliers are available in near infrared region, a Ge PIN photodiode cooled at 77K with a transimpedance (TIA) circuit and lock-in amplifier is usually used. InGaAs PIN photodiodes are more suitable than Ge PIN photodiodes for detecting low level light in the view of dark current and quantum efficiency. The detection system consists of an InGaAs PIN photodiode with a charge integrating amplifier operated at 77K. The minimum detectable power of 10^-16 W was achieved at the wavelength of 1.28μm. The integration time was 10s.
The system performance was tested by the measurement of the spectrum of singlet oxygen.